The Billiard Ball by Isaac Asimov

The Billiard Ball by Isaac Asimov (If, March 1967) begins with the narrator describing two chalk-and-cheese scientists: Priss, who is slow-thinking but (two Nobel Prizes) brilliant, and Bloom, whose genius is the practical inventions he creates from Priss’s theories. When Priss then publishes his Two Field Theory (an alternative to a Unified Field Theory) the narrator interviews him and we learn that (a) Priss is jealous of Bloom’s money, (b) their intense rivalry can be seen in their regular billiard games, and (c) Priss’s Two Field Theory suggests that anti-gravity is possible (we get an extended lecture from Priss to the narrator about gravity/mass in the universe being analogous to depressions in a rubber sheet). The interview ends with Priss disparaging Bloom’s chances of creating an anti-gravity machine.
The next part of the story sees the narrator interview Bloom, who seems to be struggling to exploit Priss’s theory. Bloom seems particularly irritated by his failure after Priss’s comments.
The story then concludes a year later, when Priss is invited, along with the Press, to a demonstration of Bloom’s anti-gravity device:

One thing was new, however, and it staggered everybody, drawing much more attention than anything else in the room. It was a billiard table, resting under one pole of the magnet. Beneath it was the companion pole. A round hole about a foot across was stamped out of the very center of the table; and it was obvious that the zero-gravity field, if it was to be produced, would be produced through that hole in the center of the billiard table.
It was as though the whole demonstration had been designed, surrealist-fashion, to point up the victory of Bloom over Priss. This was to be another version of their everlasting billiards competition, and Bloom was going to win.
I don’t know if the other newsmen took matters in that fashion, but I think Priss did. I turned to look at him and saw that he was still holding the drink that had been forced into his hand. He rarely drank, I knew, but now he lifted the glass to his lips and emptied it in two swallows. He stared at that billiard ball, and I needed no gift of ESP to realize that he took it as a deliberate snap of fingers under his nose.  p. 105 (World’s Best Science Fiction 1968, edited by Donald A. Wollheim & Terry Carr)

After an introduction where Bloom gently mocks Priss, the device is turned on (an ultraviolet column of light appears above the hole), and Bloom invites Priss to pot a ball to demonstrate the device. Priss does so, and the ball shoots through Bloom at high speed, killing him.
The remainder of the story describes the theoretical explanation of what happened (massless objects travel at the speed of light), and the narrator concludes by suggesting that, for once, Priss quickly realised how the device worked and deliberately used its effect to kill Bloom.
The main problem with this story is that, given the made-up science and the contrived events, the reader is just along for the ride. Apart from that failing it’s an engaging enough story about academic rivalry.
** (Average). 4240 words. 7,500 words.